I have read your study about Universe Three Dimensional or 4 D but our Indian mythology Universe has no figure. If there is no figure how can there be Dimension. I have not study physics more than some graduation. I think if it not possible to find the limit of any structure than you cannot fix any shape for this. Origin of Universe is still not confirm and conflicted opinion are not yet settled by any experiment. Science is saying Universe is still expanding but they are unable to say in which direction. Is it round, rectangular, triangular, oval or cylindrical etc? Like with one eye it is difficult to percept depth the same way low Cosmic Energy cannot percept the depth of Universe. In my view it should be multi-dimensional.
In physics, our three-dimensional space is viewed as embedded in 4-dimensional space-time, called Minkowski space (see special relativity). The idea behind space-time is that time is hyperbolic-orthogonal to each of the three spatial dimensions.
In mathematics, analytic geometry (also called Cartesian geometry) describes every point in three-dimensional space by means of three coordinates. Three coordinate axes are given, each perpendicular to the other two at the origin, the point at which they cross. They are usually labeled x, y, and z. Relative to these axes, the position of any point in three-dimensional space is given by an ordered triple of real numbers, each number giving the distance of that point from the origin measured along the given axis, which is equal to the distance of that point from the plane determined by the other two axes.
Other popular methods of describing the location of a point in three-dimensional space include cylindrical coordinates and spherical coordinates, though there are an infinite number of possible methods. See Euclidean space.
Another mathematical way of viewing three-dimensional space is found in linear algebra, where the idea of independence is crucial. Space has three dimensions because the length of a box is independent of its width or breadth. In the technical language of linear algebra, space is three dimensional because every point in space can be described by a linear combination of three independent vectors. In this view, space-time is four dimensional because the location of a point in time is independent of its location in space.
Three-dimensional space has a number of properties that distinguish it from spaces of other dimension numbers. For example, at least 3 dimensions are required to tie a knot in a piece of string . Many of the laws of physics, such as the various inverse square laws, depend on dimension three .
The understanding of three-dimensional space in humans is thought to be learned during infancy using unconscious inference, and is closely related to hand-eye coordination. The visual ability to perceive the world in three dimensions is called depth perception